Political science

i have quiz now and one of the question is this and if can help me on the others i will be deal with you the quiz is 10 questoins within 5 min only if you know poloitical science good contract me thanks, please only if you know the answer of this question and you solve it quckly 

The term "revolving door" explain: 

a- the architectural design of the capitol.

b- equal opportunity within the puplic sector.

c- voting patterns.

d- the ongoing trancparency of govenment.

e- elected officials moving from office to the private sector